The document EP 1 890 760 describes a medical connector with a first end known as the “upstream end”, intended to be connected to a catheter connected to a patient; and a second end, referred to as “downstream end”, intended to be interlinked with a device for sampling or injection of liquids through a male luer connector. In this document, reference is made to the terms “upstream end” and “downstream end” regardless of the direction of the flow of liquid.
In practice, this connector has a chamber supported at its base by a connector constituting the upstream end of the connector itself. The free end of the chamber, opposite the base, is intended for receiving, by friction, the tip of a male luer connector. The passage of the liquid between the catheter connected to the upstream end of the connector and the end of the male luer is ensured through a needle secured by the body of the joint. The needle extends to the chamber and opens into the terminal end of said chamber.
The needle is sheathed and maintained in the cavity of a resilient seal that has, in the thickness of its free terminal end, a slit or a similar opening allowing the needle to pass through when the resilient seal is compressed in the connected position vis à vis the connector.
In practice, this type of connector is used both for blood sampling and the injection of parenteral bags. In both cases, once the operation is completed, the catheter is cleaned with saline or alcohol.
However, the connector described above, which produces adequate results, can be improved.
The return of the resilient seal to its original position upon disconnection from the connector causes negative pressure at the terminal end of the needle. This phenomenon thus generates a suction of liquid present in the catheter, and leads at the same time to the pumping of the patient's blood to the base of the catheter, which causes obvious hygiene problems. The catheter clogs and creates a biofilm that might be infected.
To solve this problem, the document WO2008/052140 describes a connector whose needle has two longitudinal slits in which, when not connected, protrusions on the inner wall of the resilient seal are created. Insofar as these protrusions are only formed on part of the circumference of the seal, the liquid from the uncovered slits flows from both sides of the slits, in the upstream as well as the downstream direction. In other words, during connection, the entire volume between the barrel of the needle and the inner wall of the resilient seal is filled with liquid. Given the presence of flanges over the entire height of the resilient seal, a residual volume of liquid between the flanges on either side of the lateral holes will remain in the disconnected position. This stagnant fluid cannot be purged to the extent that the holes are clogged after disconnection. As a result, there is an obvious risk of contamination.
The document WO2006/013433A1 describes a similar connector except that the lateral holes are never closed. As previously described, because of the shape of the resilient seal, a residual volume of liquid remains between the wall of the seal and that of the needle after disconnection.